This follows from Garrett's fantastic answer here: In Python, given x-value on 2D Bezier Curve, return y-value
(EDIT: question generalised as per suggestion)
Say we have a Python file Foo.py containing the function X(p,q)
I would like to set things up so that my scripts can call X(...), rather than have to copy-paste its definition into each script that wants to invoke it.
How to accomplish this? And where is the right place to put Foo.py?